The IAU Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE) has been given the responsibility by the International Astronomical Union to define the rotational elements of the planets, satellites, asteroids, and comets of the solar system on a systematic basis and to relate their cartographic coordinates rigorously to the rotational elements.

In practice, the Working Group (WG) has accomplished this by issuing a report after every (triennual) IAU General Assembly, which describes the current recommended models for the cartographic coordinate and rotational elements of all planetary bodies where such detailed knowledge exists, e.g. usually via collection by spacecraft.

History

The IAU Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites was established as a consequence of a resolution adopted by Commissions 4 and 16 at the IAU General Assembly at Grenoble in 1976. The resolution reads (IAU Trans. XVIB, p. 144):

Commissions 4 and 16 noting that (a) confusion exists regarding the present rotation elements of some of the planets (b) extensive amounts of new data from radar observations and by direct imaging from spacecraft have made cartography of the surfaces of the Moon, Mercury, Venus, and Mars a reality (c) there will be an extension of these techniques to the mapping of larger satellites of Jupiter and Saturn in the near future

assert that (a) to avoid a proliferation of inconsistent cartographic and rotational systems, there is a need to define the rotational elements of the planets and satellites on a systematic basis and to relate the new cartographic coordinates rigorously to the rotation elements.

and therefore recommend that (1) Comission 4 (Ephemerides) and Comission 16 (Physical Study of Planets and Satellites) establish a Joint Working Group to study the cartographic coordinates and rotational elements of the planets and satellites and to report recommendations at the next general assembly of the IAU.

After issuing its first report at the IAU General Assembly at Montreal in 1979, the need for the WG's efforts to continue was recognized, and its existence has been renewed at every IAU meeting since. The WG is currently an Inter Division Working Group of the IAU, operating under the auspices of IAU Division F (Planetary Systems and Bioastronomy) and Division A (Fundamental Astronomy). At the IAU General Assembly in Sydney in 2003, it was recognized that similar work is now required about asteroids and comets. The WG was therefore assigned to consider the cartographic coordinates and rotational elements of these bodies. Reflecting this additional responsibility, the name of the WG was changed (shortened) to the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements.

The WG was also recognized as a working group of the International Association of Geodesy beginning with its third report (issued in 1986). This affiliation was dropped after its tenth report (issued in 2007) due
to a lack of communication with the IAG, but it may be re-established in the
future.

It was also recognized as a working group by the Committee on Space Research beginning with its third report until its sixth report (issued in 1996). COSPAR sponsorship did not continue primarily due to a strong preference that COSPAR working groups hold regular scientific symposia, which was considered outside the needs of the WG. In addition, COSPAR working groups have limited lifetimes.

The first and long time chair of the WG (1979-1997) was the late Merton E. Davies. Membership in the WG has generally changed at least to some extent with the issuance of every report.

Working Group Members

Current WG members are listed below, and past members are as indicated in the author list of the publications cited below.

Current WGCCRE Report

References

The first report of the WG was presented to the General Assembly at Montreal in 1979 and published in the Trans. IAU XVIIB, 72-79, 1980. The report with appendices was published in Celestial Mechanics 22, 205-230, 1980. The guiding principles and conventions that were adopted by the Group and the rationale for their acceptance were presented in that report and its appendices. The second report of the Working Group was published in the Trans. IAU XVIIIB, 151-162, 1983, and also with an appendix and references in Celestial Mechanics 29, 309-321, 1983. The following table summarizes the references to all the reports, and the reports are listed in detail below.

In our 2009 report, the WG stated: At the request of various individuals and missions, in the coming triennium the Working Group will consider providing limited updates to its recommendations via its website. This is in order to address a cited need to update recommendations more often than every three years, e.g. for use by operational missions and for updated cartographic products. The WG has now three times provided formal recommendations to the NASA/DLR/ASI Dawn mission at their request, regarding the coordinate system for Vesta. At the request of IAU Division F President Giovanni Valsecchi, the WG has also made a formal recommendation regarding the coordinate system for Vesta. We include a link to that recommendation in the table below and provide a reference at the bottom of this webpage.